Objective To explore the relationship between plasma cortisol level and elderly depressive symptoms. Methods Data was collected from the Rugao Longevity and Ageing Study （RuLAS） in 2017， including 1 744 older Chinese （aged from 70 to 89）. The Geriatric Depression Scale （GDS-15） was used to examine the depressive symptoms in participants （≥ 5 points as depressive）； morning blood collection was used to measure the glucose and plasma cortisol level； face to face multidimensional health assessment questionnaire was also administrated. Physical exams were performed by trained physicians. Results The prevalence of depression symptoms in Rugao elderly population was 16.5%（288/1 744）； in obese elderly people （BMI ＞ 28.0 kg/m2 ）， the cortisol level ［（13.60±3.99） μmol/dl］ of the depressed elderly was significantly higher than that of the non-depressed group ［（11.51±4.06） μmol/dl］， and the difference was statistically significant （t=2.939， P＜ 0.01）； In the obese group， after adjusting demographics， healthy behaviors and other factors， the increase in plasma cortisol levels was associated with an increased risk of depressive symptoms in the elderly （OR=1.22， 95%CI=1.08-1.37，P＜ 0.05）. Conclusions In obese elderly people in Rugao， elevated plasma cortisol levels are associated with the risk of depressive symptoms.